Various methods and apparatus for cleaning and sorting culinary items have been proposed heretofore. See for example U.S. Pat. Nos. 3,247,858; 3,483,877; and 3,486,939. As pointed out in U.S. Pat No. 3,486,939 most of these prior proposals have had limitations in operational capacity because of the inherent handling time involved in mechanically sensing and sizing the configuration of the object to be sorted or classified. Also, despite the use of various types of automated equipment these prior systems have required the presence of attendants to carry out manual sorting operations or the like.
The apparatus described in U.S. Pat. No. 3,486,939, which is designed to overcome prior limitations on operational capacity and reduce the number of attendants required in the operation, involves separating magnetically responsive chinaware from magnetically responsive silverware by passing the silverware through a grid which retains the chinaware, and then passing the separated items through a number of stations whereby the various articles are classified and isolated from each other. The silverware, for example, is passed through several magnetic stations of different field strengths, the effectiveness of the separations being dependent upon one type of silverware (e.g., spoons) being selectively removed from other magnetically responsive silverware by virtue of the strength of the particular magnetic field through which they pass. Thus, for the silverware alone the use of three different magnetic stations of different field strengths is described. In addition, the system involves several operations in which operating personnel participate.
U.S. Pat. No. 3,508,183 describes magnetically responsive silverware and chinaware for use with the apparatus of U.S. Pat. No. 3,486,939. Such articles contain a preselected quantity of magnetically attractive particles discriminately positioned within article-shaped non-magnetic material so that the article can be attracted and moved in response to the controlled magnetic field. Articles having a greater quantity of magnetically attracted particles are responsive to weak magnetic fields while those containing less particles are attracted only by the strongest fields.